Retaining device for pneumatic drills



May 2, 1939. v. K. NELSON 2,156,510

RETAINING DEVICE FOR PNEUMATTC DRTLLS Filed July 18, 1938 Unoen for i U Y Yiclivr Kar] Ne1s0n I I I I j Patented May 2, 1939 UNITED RETAINING DEVICE FOR PNEUMATIC DRI LLS

8 Claims.

My invention appertains in particular to rock drills of the drifter and sinker types in which a steel is worked by the impacts of blows delivered to it by a pneumatically actuated piston.

My invention has for-its object to provide an efficient and serviceable retaining device in the chuck by which the steel can be keyed at will in order that it may be readily withdrawn from a hole. A manual control is supplied on the front head by which the user can eifect the keying of the steel by depression of a keeper and release the steel by retracting the keeper.

The invention provides a mechanism that operates to firmly wedge the steel in the drill while in action and facilitate its removal from a hole in which it has become lodged.

In the accompanying drawing, Figure l is a fragmentary elevation, partly in section, of a drilling machine incorporating the invention. The view shows the front head portion.

Figure 2 is a front end view thereof.

Figure 3 is a cross section taken on line 3-3 of Figure l depicting the retaining device in its released position.

.-,- Figure 4 is a similar section but depicting the retaining device in its locked position.

Figure 5 is a detail cross section taken on line 5-5 of Figure 3 showing the mounting of the keeper.

Figure 6 is an elevation of the chuck.

Figure 7 is a view of a section of the steel and a key that engages a keyway provided in it.

Figure 8 is a view of the keeper.

Like numerals of reference designate similar 5 parts in each figure of the drawing.

The usual front head of the machine is gen erally denoted at 9 and is shown as equipped with the buffer springs Ill, of which the rods H secure it to the cylinder l2. The chuck l3 rotates in the front head in customary manner in the operation of the machine. .The steel I4 is of a polygonal cross section and is inserted in a similar shaped bore of the chuck. The unshanked steel abuts the anvil block, not shown, 45 as will be well understood.

In carrying out the invention, the shouldered annulus 15 on the chuck, that is made a running fit in the bore of the front head, is supplied with a radial key slot l6 leading inwardly to the bore transversely of one of the flats thereof. A keyway or notch H is furnished in the steel for registry with said slot. The outer part of the slot is abruptly widened circumferentially of the chuck, presenting a general T-shaped opening in cross section defined by the face Ilia at right angles to the radial extent of the slot. The face is drilled at each side to provide recesses iii.

A key 59 is slidably fitted in the slot and formed with Wings that overlie the recesses [8. The wings present inner shoulders engaged by compression springs 2i seated in the recesses I8. The wings are shown as equipped with pilots 22 engaged in the springs.

The back 23 of the key is curved to conform to the curvature of the bore of the front head, and is supplied with a medial ball seat 24 in the nature of a spherical depression. The seat is receptive to a hardened steel ball 25. The springs 2i function to urge the key outwardly, as will be apparent, and normally hold it against the bore of the front head as is shown in Figure 3. The l key in this position is clear of the bore of the chuck and therefore is disengaged from the keyway ii.

The ball is used to wedge the key in an advanced position, as shown in Figure 4, and for this purpose a boss 26 is fashioned on the front head with a radial hole 21 in alignment with the seat 24. A keeper 28 is fitted in the boss and conmeans consist of a nodule 29 formed on the shank and slidable in a groove 36 in the wall of the hole 21. At the inner end of the groove is a c-ircumferentially extending recess 3i, and at the outer end is a similar recess 32. The grooved part of the hole is thus supplied with a double bayonet slot.

By pushing the keeper inwardly and giving it a part turn, it is secured in one position by reason of the engagement of the nodule in the recess 3|. Upon release it can be pulled outwardly and turned to likewise lock it in the other position. The groove extends to the end of the boss which is furnished with a screw cap 33 for assembly of the ball and the keeper. When the keeper is in its inner position the end face 34 of its shank is flush with the bore of the front head, and when it is shifted to the outer position the hole accommodates the ball. The keeper is made of steel and preferably magnetized to attract the ball so that in its normal outer position the ball is retained in the hole towhich it has access.

In the operation of the machine, when it is required to use the retaining device the keeper 28 is inwardly urged and so soon as the ball contacts the key the latter is shifted inwardly into engagement with the keyway l1. As the chuck revolves, the ball drops into the seat 24 and in the continued rotation is carried around with the chuck in contact with the bore of the front head which constitutes a race-Way for it. Since the steel is now retained, the mounted machine in being fed backwards by the crank of the mount will withdraw the steel with it. Upon withdrawal, the retaining device is released by shifting the keeper to its outer position which permits the ball to resume its normal position in the hole 21.

It is manifest that the retaining device is applicable to different classes of drilling machines such as stopers, liners, sinkers, or pluggers. Moreover, such modifications and changes may be made as come within the spirit and scope of the appended claims.

I claim:

1. The combination in a pneumatic drill, of a front head having its bore interrupted by a hole, a chuck journalled in said bore and having an axial bore receptive to a steel, a dep-ressible key mounted in said chuck in alignment with said hole for retaining said steel, a loose element normally confined in said hole and adapted to be urged into the bore of said front head to depress said key, means for effecting such displacement of said element, and means retaining said element against dislodgment from said key whereby said element is carried around the bore of the front head in the rotation of the chuck.

2. The combination in a pneumatic drill, of a front head having its bore interrupted by a hole, a chuck journalled in said bore and having an axial bore receptive to a steel, a depressible key mounted in said chuck in alignment with said hole for retaining said steel, a ball normally confined in said hole so as to be urged into the bore of said front head to depress said key, means for effecting such displacement of said ball, and means retaining said ball against dislodgment from said key whereby said ball is carried around the bore of the front head in the rotation of the chuck.

3. The combination in a pneumatic drill, of a front head having its bore interrupted by a hole, a chuck journalled in said bore and having an axial bore receptive. to a steel, a depressible key mounted in said chuck in alignment with said hole for retaining said steel, said key having a depressed seat for registry with said hole, a ball normally confined in said hole so as to be urged into the bore of said front head to engage said seat and depress the key, and means for effecting such displacement of the ball from the hole whereby it is caused to travel around the bore of the front head in the rotation of the chuck to maintain the key in depressed position.

4. The combination in a pneumatic drill, of a front head having its bore interrupted by a hole, a chuck journalled in said bore and having an axial bore receptive to a steel, a key radially slidable in the chuck for engaging a keyway in said steel when inwardly depressed, said key having a depressed seat for registry with said hole, a spring outwardly urging said key, a ball normally confined in said hole so as to be urged into the bore of said front head to engage said seat and depress the key, and means for effecting such displacement of the ball from the hole whereby it is caused to travel around the bore of the front head in the rotation of the chuck to maintain the key in depressed position.

5. The combination in a pneumatic drill, of a front head having its bore interrupted by a hole, a chuck journalled in said bore, a steel inserted in said chuck and having a keyway in alignment with said hole, a key radially slidable in said chuck for engaging said keyway when inwardly depressed, said keyway having a top face curved to the curvature of the bore of the front head for contact therewith, there being a depressed seat in said top face for registry with said hole, a spring outwardly urging said key, a ball normally confined in said hole so as to be urged into the bore of said front head to engage said seat and depress the key, and means for effecting such displacement of the ball from the hole whereby it is caused to travel around the bore of the front head in the rotation of the chuck to maintain the key in depressed position.

6. The combination in a pneumatic drill, of a front head having its bore interrupted by a hole, a chuck journalled in said bore and having a bore receptive to a steel, said chuck also having a radial slot leading inwardly to its bore and circumferentially enlarged at its outer end, said chuck also having recesses extending inwardly from the enlarged outer end of the slot, a key radially slidable in said slot for retaining a steel in the bore of the chuck, said key having wings disposed in the enlarged outer end of the slot and having an incurvate back for engaging the bore of the front head, said back having a spherical seat for registry with said hole, compression springs seated in said recesses and shouldered against said wings to urge the key outwardly, a ball normally confined in said hole so as to be urged into the bore of the front head to engage said spherical seat and depress the key, and means for effecting such displacement of the ball whereby it is caused to travel around the bore of the front head in the rotation of the chuck to maintain the key in depressed position.

7. A structure as defined in claim 3, in which the means for effecting displacement of the ball from the hole consists of a manually operablekeeper slidable in the hole and provided with a device by which it is releasably locked to close the hole.

8. The combination in a pneumatic drill, of. a front head having its bore interrupted by a hole, a chuck journalled in said bore and having an axial bore receptive to a steel, a depressible key mounted in said chuck in alignment with said hole for retaining said steel, said ,key having a depressed seat for registry with said hole, a ball normally confined in said hole so as to be urged into the bore of said front head to engage said seat and depress the key, and means for effecting such displacement of the ball from the hole whereby it is caused to travel around the bore of the front head in the rotation of the chuck to maintain the key in depressed position, said means consisting of a keeper having a shank slidable in the hole with an inner end face for abutting the ball and lying flush with the bore of the front head when the keeper is shifted to an inner position, and a bayonet slot mechanism for releasably securing the keeper in said inner position.

VICTOR KARL NELSON. 

